1. Field of the Invention
This invention relates to a new and valuable 1,1,1-trichloroethane stabilized composition. More particularly, this invention relates to an improved 1,1,1-trichloroethane stabilized composition which contains, as stabilizer therefor, a three component stabilizer system. This invention is directed to improving the stability of 1,1,1-trichloroethane to reduce the marked tendency thereof to undergo decomposition.
2. Discussion of Prior Art
It is well known that halogen hydrocarbons such as vinyl chloride, vinylidene chloride, trichloroethane, trichloroethylene, perchloroethylene, and other aliphatic chlorinated hydrocarbons very easily undergo decomposition. This decompostion generally takes place at the simultaneous formation of acids and is caused, among other things, by the presence of light, air, or traces of water. It is further known that the splitting off of acids is greatly promoted by the presence of certain metals. Thus, for example, the decomposition reaction is catalyzed by iron, aluminum, magnesium and alloys of such metals.
The decomposition reaction can be so violent in the case of some of these compounds, that the further use and processing of these halogen hydrocarbons in metal vessels is possible only with the greatest of difficulty, if at all. As noted above, light serves to promote the decomposition further complicating further use and processing of the halogenated hydrocarbons.
This defect is especially marked in the case of 1,1,1-trichloroethane which is more inclined to split off hydrochloric acid and then blacken than any of the other above-named chlorinated hydrocarbons. The decomposition reaction can progress to the complete resinification of the material. Accordingly, its usefulness as such is severely limited. For industrial use, the 1,1,1-trichloroethane is employed only together with an added stabilizer.
Many agents have been suggested heretofore as stabilizers for 1,1,1-trichloroethane. These include dialkylsulfoxides, dialkylsulfites, dialkylsulfides, 1,4-dioxanes, epoxides, monoketones, trialkylsilylethers, trialkyl compounds of tin and lead, nitroalkanes, secondary and tertiary alcohols, nitriles, acetylene alcohols, oxazirines, thiazirines, oxaphosphorines and thiaphosphorines. Usually, these stabilizing agents must be used in large quantities to provide an adequate stabilizing effect. Such is not always desirable. When large quantities are employed, the 1,1,1-trichloroethane so stabilized takes on the character of a mixture of solvents; as such its utility is limited. Additionally, use of dioxane and a number of the other conventionally employed stabilizers in such large quantities can present problems of toxicity. Certain of the conventionally used stablizers set forth above have also proved undesirable due to the color which they impart to the 1,1,1-trichloroethane, while others are entirely unsuitable due to their great chemical reactivity with the agents to be treated where they are used up in the reaction and the stabilizing effect initially produced is gradually lost with decomposition setting in rapidly. Still another group of known stabilizers is characterized by the groups great sensitivity to hydrolysis is oxygen, and therefore, this group finds only limited application.
It has thus become desirable to provide a stabilizer system which will stabilize 1,1,1-trichloroethane wherein trichloroethane. Moreover, it is desirable to provide a stabilizer composition which will inhibit the catalytic effect of metals such as iron, aluminum and zinc. Still moreover it is desirable to provide stabilizer composition which will stabilize 1,1,1, trichloroethane in the vapor phase as well as in the liquid phase.
Still moreover it is desirable to provide a stabilized 1,1,1, trichloroethane composition which passes the test set forth in the United States military specification MIL-T- 7003. This testing method is considered to be one of the strictest and thus measures the overall stability of the 1,1,1, trichloroethane particularly with respect to the amount of catalytic water present which tends to effect the decomposition. Thus, this military specification test employs a certain amount of water during the test procedure.